(1) Field of the Invention
The present invention relates to optic devices, and particularly to a duplex focusing device which is installed in a duplex light transceiver module, and more specifically the present invention provides a focusing means capable of altering a ball lens assembly controlled by the light transceiver module so that light can be easily coupled to an optical fiber and an optic detector reliably.
(2) Description of the Prior Art
In current optic communication systems, laser diodes are generally used as light sources. A packaged laser diode is as a laser diode element 1a. A packaged light detector is as a light detection element 2a. Referring to FIGS. 1A and 1B, it is seen that a laser diode element 1a and a light detection components 2a are mounted inside a metal fixture 3 as a light transmitting module 1a and a light receiving module 2. Then the light transmitting module 1a, light receiving module 2 and a body 4, are packaged as a duplex light transceiver module 5. The interior of the body 4 is provided with an optical filter 6. The upper and lower surfaces of the optical filter 6 are evaporation-coated with mediums of different transmission index. Thus it causes that light radiated from laser diode element 1a is coupled to an optical fiber 9a via the optic filter 6. Then the light that is completely reflected to a light detector 2a through the optical filter 6.
The optic filter 6 is fixed to a frame 8 of a filter holder 7 and the filter holder 7 is inserted into the body 4. Next, the optic filter 6 is adjusted to an optimum orientation to assure that reflection or refraction of the incident light radiating into the optic filter has an optimum result. That is, after the filter holder 7 is inserted into the fixture 3. The holder 7 must be adjusted to an optimum orientation with respect to the optic filter 6, and this step is inconvenient for the operation.
Moreover, in the prior art, ball lenses 9 are mounted directly to both the laser diode element 1a and the light detector 2a. As a result, displacement of the laser diode element 1a will cause the focusing lens into simultaneous movement. Thereby, the focusing positions of light to the optical fiber 9a and the light detector 2a are changed greatly. Therefore the coupling operation is difficult and the optical property is not preferred.
Accordingly, the primary object of the present invention is to provide a duplex focusing device installed a duplex light transceiver module for the transmission of light signals. The duplex focusing device comprises a ball lens assembly having a first lens and a second lens both being symmetrical half ball matching to each other. A layer of wavelength-division medium being placed between the first and second lens to ensure that light transmitted from a laser diode will transmit through the ball lens assembly; thereby, the light transmitting into the ball lens assembly will have a part being reflected by the second lens.
Another object of the present invention is to provide duplex focusing device, wherein the body serves for receiving and fixing the ball lens; the body being formed by a front part and a rear part; each of the front part and the rear part having an annular rim and a correspondingly annular protrusion linked to said annular rim; the annular protrusion being formed a notched groove to accommodate ball lens assembly so that both orientations of the first lens and the second lens are adjustable with respect to the body.
A further object of the present invention is to provide a duplex focusing device, wherein the duplex focusing device is placed in a duplex light transceiver module; and the duplex light transceiver module has an optical fiber connected element, a light receiving module and a light transmitting module which are arranged around the duplex focusing device.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.